US7336603B2 - Internet telephone system ensuring communication quality and path setting method - Google Patents

Internet telephone system ensuring communication quality and path setting method Download PDF

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US7336603B2
US7336603B2 US09/816,705 US81670501A US7336603B2 US 7336603 B2 US7336603 B2 US 7336603B2 US 81670501 A US81670501 A US 81670501A US 7336603 B2 US7336603 B2 US 7336603B2
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path
label switch
voice
label
band
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US20010024438A1 (en
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Kazuhiko Sugiyama
Kei Akiyoshi
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Juniper Networks Inc
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Juniper Networks Inc
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
    • H04L41/50—Network service management, e.g. ensuring proper service fulfilment according to agreements
    • H04L41/5003—Managing SLA; Interaction between SLA and QoS
    • H04L41/5009—Determining service level performance parameters or violations of service level contracts, e.g. violations of agreed response time or mean time between failures [MTBF]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
    • H04L41/50—Network service management, e.g. ensuring proper service fulfilment according to agreements
    • H04L41/508—Network service management, e.g. ensuring proper service fulfilment according to agreements based on type of value added network service under agreement
    • H04L41/5087—Network service management, e.g. ensuring proper service fulfilment according to agreements based on type of value added network service under agreement wherein the managed service relates to voice services
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/302—Route determination based on requested QoS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/302—Route determination based on requested QoS
    • H04L45/306—Route determination based on the nature of the carried application
    • H04L45/3065—Route determination based on the nature of the carried application for real time traffic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L45/00—Routing or path finding of packets in data switching networks
    • H04L45/50—Routing or path finding of packets in data switching networks using label swapping, e.g. multi-protocol label switch [MPLS]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/10—Architectures or entities
    • H04L65/102—Gateways
    • H04L65/1023—Media gateways
    • H04L65/103—Media gateways in the network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/10—Architectures or entities
    • H04L65/102—Gateways
    • H04L65/1033—Signalling gateways
    • H04L65/104—Signalling gateways in the network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1083—In-session procedures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/60—Network streaming of media packets
    • H04L65/75—Media network packet handling
    • H04L65/752—Media network packet handling adapting media to network capabilities
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M7/00—Arrangements for interconnection between switching centres
    • H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
    • H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
    • H04M7/1245—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks where a network other than PSTN/ISDN interconnects two PSTN/ISDN networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0016—Arrangements providing connection between exchanges
    • H04Q3/0025—Provisions for signalling
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04Q—SELECTING
    • H04Q3/00—Selecting arrangements
    • H04Q3/0016—Arrangements providing connection between exchanges
    • H04Q3/0029—Provisions for intelligent networking
    • H04Q3/0045—Provisions for intelligent networking involving hybrid, i.e. a mixture of public and private, or multi-vendor systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
    • H04L41/50—Network service management, e.g. ensuring proper service fulfilment according to agreements
    • H04L41/5003—Managing SLA; Interaction between SLA and QoS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
    • H04L65/1066—Session management
    • H04L65/1101—Session protocols

Definitions

  • the present invention relates to a voice data communication system (i.e., Internet telephone system) using an Internet protocol (IP) network, and more particularly, to an Internet telephone system capable of ensuring the quality of voice data communication (communication quality or QoS (Quality of Service)) and a path setting method.
  • IP Internet protocol
  • the ITU-T recommendation prescribes a method for solving a problem of the conversion between a telephone number and an IP address and a method for converting (mapping) voice data into an IP packet and, however, it prescribes no method for ensuring communication quality.
  • the IETF proposes only a schematic standard for Internet telephone system.
  • predetermined communication quality must be ensured by preventing the disposition of a voice packet on the IP network and by reducing the delay in transfer of the packet to realize the Internet telephone system to satisfy user's desire.
  • an Internet telephone system implements voice communication between a telephone subscribing to a first voice network and a telephone subscribing to a second voice network via a network using an Internet protocol.
  • the internet telephone system constitutes the network, and includes a plurality of label switch routers each of which uses a label switching technique.
  • a first media gateway is connected across a first specific label switch router among the plurality of label switch routers and a first signaling transfer point connected to the first voice network, and assembles/resolves a VoIP packet.
  • a second media gateway is connected across a second specific label switch router among the plurality of label switch routers and a second signaling transfer point connected to the second voice network, and assembles/resolves a VoIP packet.
  • a path control unit checks whether or not there is a path having a residual band larger than a band necessary for transferring the VoIP packet between the first specific label switch router and the second specific label switch router. When it is determined that there is not the path, the path control unit sets a new path having a band that is equal to or more than a double band of the necessary band.
  • a packet control unit is connected to the path control unit, and instructs the first media gateway and the second media gateway to transfer the VoIP packet via the path that is checked or set by the path control unit.
  • a path to which a band is ensured is set on a network using an Internet protocol connected between the first voice network and the second voice network.
  • a path control unit determines whether or not there is a path having a residual band larger than a band necessary for transferring a VoIP packet between two edge label switch routers. Also, the path control unit sets a new path having band that is equal to or more than a double band of the necessary band between the two edge label switches by the path control unit, when it is determined that there is not the path.
  • a call control apparatus sets a path to which a band is ensured on a network using an Internet protocol connected between a first voice network and a second voice network to execute voice communication between a telephone subscribing to the first voice network and a telephone subscribing to the second voice network.
  • the call control apparatus includes a path control unit which determines whether or not there is a path having a residual band larger than a band necessary for transferring a VoIP packet between two edge label switch routers. When it is determined that there is not the path, the call control apparatus sets a new path having a band that is equal to or more than a double band of the necessary band between the two edge label switch routers.
  • a packet control unit controls a media gateway connected to the two edge label switch routers to transfer the VoIP packet via a path having the residual band or the new-set path.
  • a router is used for a network using an Internet protocol connected between a first voice network and a second voice network to implement voice communication between a telephone subscribing to the first voice network and a telephone subscribing to the second voice network.
  • the router sets a path having a band that is equal to or more than a double band of a band necessary for transferring a VoIP packet under the control of a call control apparatus, thereby establishing a plurality of connections in the path.
  • a computer program product for implementing a call control apparatus sets a path to which a band is ensured on a network using an Internet protocol connected between a first voice network and a second voice network to execute voice communication between a telephone subscribing to the first voice network and a telephone subscribing to second voice network.
  • the computer program product includes the steps of determining whether or not there is a path having a residual band larger than a band necessary for transferring a VoIP packet between two edge label switch routers and, when it is determined that there is not the path, setting a new path having a band that is equal to or more than a double band of the necessary band between two edge label switch routers, and controlling a media gateway connected to the two edge label switch routers to transfer the VoIP packet via the path having the residual band larger than the necessary band or the new-set path.
  • FIG. 1 is a block diagram showing the structure of a conventional Internet telephone system using an IP network
  • FIG. 2 is a diagram showing a sequence for implementing communication in the Internet telephone system in FIG. 1 ;
  • FIG. 3 is a diagram showing the structure of an Internet telephone system according to a first embodiment of the present invention.
  • FIG. 4 is a diagram for explaining the relationship between a label switching path and the connection in the Internet telephone system in FIG. 3 ;
  • FIG. 5 is a flowchart for explaining the operation of a label switching control unit of a label switch router shown in FIG. 3 ;
  • FIG. 6 is a diagram showing the operation of the Internet telephone system in FIG. 3 ;
  • FIG. 7 is a diagram showing the construction of an Internet telephone system according to a second embodiment of the present invention.
  • a third Internet telephone system is constituted by combining the first Internet telephone system and second Internet telephone system, thereby enabling the voice communication even between the normal telephone and the personal computer.
  • This Internet telephone system uses an Media Gateway Control Protocol (MGCP).
  • MGCP Media Gateway Control Protocol
  • this Internet telephone system comprises a call agent (CA) 13 which is connected to an IP network (e.g., Internet) 11 and a No. 7 signal-system network (e.g., public telephone network) 12 .
  • the call agent 13 is also called a Media Gateway Controller (MGC).
  • Gateways 14 and 15 comprise media gateways (MG) 141 and 151 connected to the IP network 11 and call agent 13 and signaling transfer points (STP) 142 and 152 connected to the No. 7 signal-system network 12 , respectively.
  • FIGS. 1 and 2 The operation of the second Internet telephone system will be described with reference to FIGS. 1 and 2 .
  • a sender telephone or an originator: not shown
  • an addressed telephone or a destination: not shown
  • Information indicating the relationship thereof is stored in a memory of the call agent 13 .
  • the sender telephone calls the gateway 14 and notifies a telephone number of the addressed telephone.
  • the signaling transfer point 142 of the gateway 14 transmits a connection request signal IAM (Initial Address Message) 1 including end point information to the call agent 13 via the No. 7 signal-system network 12 (sequence a).
  • IAM Initial Address Message
  • the end point information includes an IP address of the gateway 14 and a telephone number of the addressed telephone.
  • the call agent 13 When the connection request signal IAM 1 is received from the signaling transfer point 142 , the call agent 13 specifies the gateway 15 associated with the addressed telephone on the basis of the end point information in the received connection request signal. Then, the call agent 13 transmits a connection generating request signal CRCX 1 to the media gateway 141 via the IP network 11 to establish the connection to the specified gateway 15 (sequence b).
  • the media gateway 141 executes a connection establishing process to the gateway 15 and also transmits an answer signal ACK 1 for notifying the end of the connection establishing process to the call agent 13 via the IP network 11 (sequence c).
  • This answer signal ACK 1 includes session description such as a protocol version.
  • the call agent 13 transmits a connection establishing request signal CRCX 2 to the media gateway 151 (sequence d).
  • the media gateway 151 transmits an answer signal ACK 2 including the session description to the call agent 13 (sequence e).
  • a one-way path is established from the media gateway 141 to the media gateway 151 .
  • the call agent 13 transmits a connection request signal IAM 2 to the signaling transfer point 152 via the No. 7 signal-system network 12 (sequence f).
  • the signaling transfer point 152 calls the addressed telephone corresponding to the telephone number included in the connection request signal IAM 2 from the call agent 13 .
  • the signaling transfer point 152 transmits an answer signal ACM (Address Complete Message) to the call agent 13 to notify the start of call of the addressed telephone (sequence g).
  • ACM Address Complete Message
  • the call agent 13 transfers it to the signaling transfer point 142 (sequence h). This results in entering a state of calling the addressed telephone from the sender telephone.
  • the signaling transfer point 152 transmits an answer signal ANM 1 (Answer Message) to the call agent 13 (sequence i).
  • the call agent 13 transmits a connection adjusting request signal MDCX including the session description to the media gateway 141 to change connection between the media gateways 141 and 151 to be interactive (sequence j).
  • the media gateway 141 changes the state of connection based on the session description included in the connection adjusting request signal MDCX.
  • the media gateway 141 transmits an answer signal ACK 3 to the call agent 13 after changing the state of connection (sequence k).
  • the call agent 13 confirms that the interactive connection is established between the media gateways 141 and 151 , and transmits the answer signal ANM 2 to the signaling transfer point 142 (sequence l).
  • this Internet telephone system enables the voice communication via the IP network between the sender telephone and addressed telephone (sequence m).
  • the signaling transfer point 142 transmits a communication line connection end signal REL 1 (Release Message) to the call agent 13 (sequence n).
  • the call agent 13 transmits a connection release request signal DLCX 2 to the media gateway 141 (sequence o).
  • the media gateway 141 performs a connection releasing process and also transmits an answer signal ACK 4 including a connection parameter to the call agent 13 (sequence p).
  • the call agent 13 transmits a communication line release complete signal RLC 1 (Release Complete Message) to the signaling transfer point 142 (sequence q). Thereby, the signaling transfer point 142 checks the release of connection.
  • the call agent 13 transmits the connection release request signal DLCX 2 to the media gateway 151 (sequence r). Similarly to the media gateway 141 , after connection releasing process, the media gateway 151 also transmits an answer signal ACK 5 including a connection parameter to the call agent 13 (sequence s). When the release of connection is confirmed by the reception of the answer signal ACK 5 from the media gateway 151 , the call agent 13 transmits a communication line connection end signal REL 2 to the signaling transfer point 152 (sequence t). When the release of connection is confirmed by the reception of the communication line connection end signal REL 2 , the signaling transfer point 152 transmits the communication line release complete signal RLC 2 to the call agent 13 (sequence u).
  • an MGCP is used for controlling the VoIP gateways 14 and 15 from the outside. That is, the MGCP defines an interface between the call agent 13 and the media gateways 141 and 151 .
  • the call agent 13 can control the media gateways 141 and 151 and also can notify the call agent 13 of an event from the media gateways 141 and 151 .
  • FIGS. 3 to 7 A description is given of an Internet telephone system according to a first embodiment of the present invention with reference to FIGS. 3 to 7 .
  • this Internet telephone system has a call agent (CA) or call control apparatus 31 .
  • a control terminal 32 is connected to the call agent 31 .
  • An Internet protocol (IP) network 33 includes a plurality of label switch routers (LSR) 34 , 35 , 36 , 37 , and 38 .
  • a plurality of voice networks 39 and 40 includes at least telephones (or voice terminals) 41 and 42 , respectively.
  • the voice networks 39 and 40 are directly connected to the signaling transfer points 43 and 44 , respectively.
  • the signaling transfer points 43 and 44 are connected to a public telephone network and are directly connected to media gateways (MG) 45 and 46 , respectively.
  • the media gateways 45 and 46 are directly connected to label switch routers 34 and 36 , respectively.
  • the call agent 31 has an LSP control unit 311 and a VoIP packet control unit 312 .
  • the call agent 31 controls a call of the IP network and, for example, is arranged in an exchange station of the public telephone network.
  • the LSP control unit 311 stores a maximum band settable between adjacent label switch routers in an internal memory (not shown).
  • the LSP control unit 311 stores the connection relationship between the signaling transfer points 43 and 44 and the media gateways 45 and 46 in the internal memory.
  • the LSP control unit 311 stores the connection relationship between the telephones included in the voice networks 39 and 40 and the media gateways 45 and 46 in an internal memory (telephone number table) with correlation to telephone numbers of the telephones. Further, the LSP control unit 311 stores the connection relationship between the media gateways 45 and 46 and the label switch routers 34 and 36 in the internal memory.
  • Information indicative of the connection relationships is supplied, for example, through a control terminal 32 by a maintenance person.
  • connection request signals (off-hook signal and dial signal) are received from the signaling transfer points 43 and 44 .
  • the LSP control unit 311 searches the internal memory and specifies the media gateway 45 or 46 connected to the signal transfer point 43 or 44 and the label switch router 34 or 36 connected thereto.
  • the specified media gateway and label switch router are called a sender media gateway and a sender edge label switch router, respectively.
  • the LSP control unit 311 searches the telephone number table, and specifies the media gateway 45 or 46 connected to the voice network 39 or 40 including the telephone corresponding to the addressed telephone number included in the connection request signal and the label switch router 34 or 36 connected thereto, respectively.
  • the specified media gateway and label switch router are called an addressed media gateway and the addressed edge label switch router, respectively.
  • the label switch routers 35 , 37 , and 38 located between the sender edge label switch router and the addressed edge label switch router are called core label switch routers.
  • the LSP control unit 311 notifies the VoIP packet control unit 312 of addresses (IP addresses) assigned to the sender and addressed edge media gateways 45 and 46 .
  • the LSP control unit 311 manages a label switching path (LSP) on the IP network.
  • LSP label switching path
  • the LSP control unit 311 controls the sender and addressed edge label switch routers 34 and 36 and confirms the label switching path which exists therebetween.
  • the LSP control unit 311 provides a new label switching path between the sender and addressed label switch routers 34 and 36 if the necessity may arise.
  • Each of the label switching paths to be set on the IP network has a wide band capable of accommodating a plurality of connections (e.g., approximately 100 to 1000 connections are preset).
  • the label switching path has a band which is equal to or more than a plurality of times of a band necessary for transferring the VoIP packet.
  • One label switching path can accommodate a plurality of connections and, therefore, the LSP control unit 311 needs no setting of label switching path each time a connection is established. As a consequence, the load of the overall IP network is reduced.
  • the label switching path may be provided in advance between any desired two label switch routers in the LSP control unit 311 , irrespective of the connection request signal. In this case, if no congestion is caused, the label switching path needs no control or no adjustment between the label switch routers. As mentioned above, because each label switching path can accommodate a large number of connections, e.g., 100 to 1000 connections.
  • the label switching path to be preset may be provided across three or more label switch routers. The band of the label switching path may be changed in accordance with day of the week or time.
  • the VoIP packet control unit 312 notifies the addressed media gateway of a service port number assigned to the sender media gateway.
  • the VoIP packet control unit 312 notifies the sender media gateway of a service port number assigned to the addressed media gateway. Further, the VoIP packet control unit 312 notifies the sender media gateway and addressed media gateway of a fact that the connection between the sender media gateway and the addressed media gateway is established.
  • FIG. 4 shows the relationship between the label switching path and VoIP connection.
  • label switching paths 49 and 50 are sequentially established between the edge label switch routers 34 and 36 .
  • the label switching paths 49 and 50 are established similarly to, for example, the sequences shown in FIG. 2 .
  • the edge label switch routers 34 and 35 are connected for the purpose of the convenience of description.
  • a label switching path is established between two adjacent routers. Therefore, a new label switching path may be established between the edge label switch routers 34 and 35 , and an existing label switching path may be used between the core label switch router 35 and edge label switch router 36 .
  • the sender media gateway and addressed media gateway answer the notification from the VoIP packet control unit 312 , and establishes a connection through the label switching path between the sender label switch router and the addressed label switch router.
  • the sender and addressed media gateways convert analog/digital data and assemble/resolve a packet (or VoIP data) between the voice networks 39 and 40 and the IP network 33 .
  • Each label switch router has a route control unit (QoS routing protocol) and a label switching control unit (MPLS).
  • QoS routing protocol QoS routing protocol
  • MPLS label switching control unit
  • the route control unit calculates a route, information on communication quality is considered.
  • the label switching control unit uses an MPLS (Multi-Protocol Label Switching) technique to realize the assurance of band.
  • MPLS Multi-Protocol Label Switching
  • a band reservation system (RSVP: ReSerVation Protocol) and a service differentiating system (Diff-Serv: Differentiated Service) are known as techniques for ensuring the communication quality.
  • the former technique is described in the IETF RFC2205, and the latter technique is described in the IETF RFC2475.
  • the RSVP periodically optimizes a communication route and, therefore, the load is applied to the IP network.
  • the Diff-Serv throws out the packet when the congestion is caused. Then, this Internet telephone system reduces the load of the IP network, and uses the MPLS so as to ensure the communication quality.
  • the sender edge label switch router calculates the shortest route to the addressed edge label switch router under the control operation of the LSP control unit 311 .
  • the sender edge label switch router determines whether or not a connection can be established. In other words, the sender edge router determines whether or not a band necessary for transferring the VoIP packet remains in the existing label switching path. If the connection can be established, the sender edge label switch router does not establish a new label switching path. If there is not a label switching path on the shortest route and if there is no residual band for establishing the connection in existing the label switching path, the sender edge label switch router establishes a new label switching path on the shortest route.
  • the addressed edge label switch router operates in the same manner as that of the sender edge label switch router, and establishes the label switching path to obtain the shortest route to the sender edge label switch router if the necessity may arise.
  • Each label switch router located on the label switching path transfers the VoIP data as if it flowed on the label switching path by using information which is called a label.
  • the label switch router can transfer the IP packet (i.e., fast transfer), without performing the IP process.
  • the sender telephone 41 calls the call agent 31 and notifies the call agent 31 of the telephone number of the addressed telephone 42 .
  • This notification is transmitted to the LSP control unit 311 of the call agent 31 as the connection request signal IAM by the signaling transfer point 43 connected to the network 39 including the sender telephone 41 .
  • the connection request signal IAM includes a telephone number of the sender telephone 41 , telephone number of the addressed telephone 42 , and information that the transmission (and band assurance) of the VoIP packet is desired.
  • the LSP control unit 311 specifies the sender signaling transfer point 43 which transmits the connection request signal IAM.
  • the LSP control unit 311 searches the internal memory, and specifies the sender media gateway 45 connected to the sender signaling transfer point 43 and the sender edge label switch router 34 connected to the sender media gateway 45 .
  • the LSP control unit 311 specifies the addressed signaling transfer point 44 connected to the voice network 40 including the addressed telephone 42 , the addressed media gateway 46 connected to the addressed signaling transfer point 44 , and the addressed edge label switch router 36 connected to the addressed media gateway 46 , based on the addressed telephone number (step A 1 ).
  • the LSP control unit 311 determines whether or not the sender media gateway 45 and addressed media gateway 46 are specified in step A 1 (step A 2 ). If at least one of the sender media gateway 45 and addressed media gateway 46 is not specified, the LSP control unit 311 cancels processes after that. If both the sender media gateway 45 and addressed media gateway 46 are specified, IP addresses of the specified sender media gateway 45 and addressed media gateway 46 are notified to the VoIP packet control unit 312 .
  • the VoIP packet control unit 312 requests to issue a call to the sender media gateway 45 (step A 3 ).
  • the sender media gateway 45 notifies the VoIP packet control unit 312 of a service port number of the sender media gateway 45 .
  • the VoIP packet control unit 312 When the notification of the service port number of the sender media gateway 45 is received from the sender media gateway 45 , the VoIP packet control unit 312 notifies the addressed media gateway 46 of the IP address and service port number of the sender media gateway 45 and requests to issue a call (steps A 4 and A 5 ). When the notification of the service port number of the sender media gateway 45 is not received from the sender media gateway 45 , the VoIP packet control unit 312 performs a cancel process in step A 16 and cancels processes after that.
  • the addressed media gateway 46 notifies the VoIP packet control unit 312 of the service port number of the addressed media gateway 46 in accordance with the request to issue a call from the VoIP packet control unit 312 .
  • the VoIP packet control unit 312 performs a cancel process in step A 16 and cancels processes after that (step A 6 ).
  • the LSP control unit 311 checks whether or not the label switching path has already been established between the edge label switch routers 34 and 36 (step A 7 ). If the label switching path has not been established yet between the edge label switch routers 34 and 36 , the LSP control unit 311 requests the addressed edge label switch router 36 to establish the label switching path to the sender edge label switch router 34 (steps A 8 and A 9 ).
  • the addressed edge switching router 36 tries to establish the label switching path to the sender edge label switch router 34 and notifies the LSP control unit 311 of the result (step A 10 ). If the addressed edge label switch router 36 establishes the label switching path to the sender edge label switch router 34 , the LSP control unit 311 requests the sender edge label switch router 34 to establish the label switching path to the addressed edge label switch router 36 (step A 11 ). If the addressed edge label switch router 36 does not establish the label switching path to the sender edge label switch router 34 , the LSP control unit 311 performs a cancel process in step A 16 and cancels processes after that.
  • the sender edge label switch router 34 tries to establish the label switching path to the addressed edge label switch router 36 and notifies the LSP control unit 311 of the result (step A 12 ). If the sender edge label switch router 34 does not establish the label switching path to the addressed edge label switch router 36 , the LSP control unit 311 performs the cancel process in step A 16 and cancels processes after that.
  • the LSP control unit 311 notifies the VoIP packet control unit 312 of such a fact.
  • the VoIP packet control unit 312 controls the media gateway 46 and transmits an incoming call address and the IP address of the sender telephone to the addressed telephone 42 .
  • the media gateway 46 notifies the VoIP packet control unit 312 of such a fact.
  • the VoIP control unit 312 notifies the sender media gateway 45 of the IP address and service port number of the addressed media gateway 46 and requests to change the connection of call (step A 17 ).
  • the media gateway 45 converts a voice signal from the telephone 41 into the VoIP packet, adds a header including the IP address and service port number of the media gateway 46 , and transmits the VoIP packet added with the header to the media gateway 46 .
  • the media gateway 46 converts a voice signal from the telephone 42 into the VoIP packet, adds a header including the IP address and service port number of the media gateway 45 , and transmits the VoIP packet added with the header to the media gateway 45 .
  • the media gateway 45 converts the received VoIP packet into a voice signal and transmits it to the telephone 41 .
  • the media gateway 46 converts the received VoIP packet into a voice signal and transmits it to the telephone 42 .
  • the LSP control unit 311 checks whether or not a new connection can be established in the detected label switching path (step A 13 ). That is, the LSP control unit 311 checks whether or not there is an unused band necessary for the voice communication and whether or not the band necessary for the voice communication can be ensured in the detected label switching path.
  • the processing routine advances to step A 9 from step A 14 .
  • the LPS control unit 311 determines that a new connection can be established in the detected label switching path
  • the LPS control unit 311 requests the edge label switch routers 34 and 36 to establish a new connection in the detected label switching path.
  • the LSP control unit 311 requests the edge label switch routers 34 and 36 to flow the VoIP data packet between the edge label switch routers 34 and 36 via the detected label switching path (step A 15 ).
  • the voice communication via the IP network is possible between the sender telephone 41 and the addressed telephone 42 .
  • the edge label switch router 34 adds a label to the IP data packet to be transmitted from the media gateway 45 .
  • the core label switch router 35 transfers the IP packet which is transmitted by the edge label switch router 34 in accordance with the label which is added to the transmitted to IP packet (input label). In this case, the core label switch router 35 exchanges the input signal to another label signal (output label). Because the core label switch router 35 stores the relationship between the input label and the transfer destination (and output label) in the internal memory, the IP packet can be transferred at a high speed on the basis of only the input label without referring to the header of the IP packet. Only if the label which is added to the received IP packet is not stored in the internal memory, the core label switch router 35 recognizes the transfer destination by referring to the header of the IP packet.
  • the core label switch router 35 assigns a new output label and stores the relationship between the input label and the output label.
  • the edge label switch router 36 removes the label from the IP packet and transfers only the IP packet to the media gateway 46 (process 3 ).
  • the transfer of packet to the media gateway 45 from the media gateway 46 is executed in the manner similar to the foregoing.
  • the band of connection which has been established once is ensured, and the delay in transfer of the packet is decreased by using the label switch router.
  • the setting of the path is not necessary every connection because the band of label switching path is set to be large. Accordingly, the number of negotiation between the routers is decreased and the setting of path is possible in a short time in the Internet telephone system.
  • the Internet telephone system comprises a call agent (CA) or call control apparatus 71 , an MPLS server 72 of the label switching system (MPL), an IP network 80 including a plurality of label switch routers (LSR) 73 - 79 , and media gateways 45 and 46 .
  • the label switch routers 73 and 74 are called edge label switch routers while the label switch routers 75 - 79 are called core label switch routers.
  • the media gateway 45 is directly connected to the label switch router 73
  • the media gateway 46 is directly connected to the label switch router 74 .
  • the call agent 71 has a VoIP packet control unit 312 , and manages a connection between the media gateways 45 and 46 . If the assurance of band is necessary when the connection is established between the media gateways 45 and 46 , the call agent 71 requests the LSP control unit 311 of the MPLS server 72 to form the label switching path between the edge label switch router 73 and 74 .
  • the MPLS server comprises the LSP control unit 311 and a route control unit (QoS routing protocol) 721 .
  • the LSP control unit 311 answers the inquiry of an address from the VoIP packet control unit 312 , and establishes and manages the label switching path.
  • the route control unit 721 performs routing together with the edge label switch routers 73 and 74 and core label switch routers 75 to 79 .
  • the LSP control unit 311 sets the route when the route control unit 721 operates.
  • the route control unit 721 is connected to all of the label switch routers 73 - 79 , and collectively manages the label used on the IP network. Consequently, each label switch router needs no management of the label. That is, the negotiation between the routers becomes unnecessary. Since the route control unit 721 manages the labels in a lump, it is possible to transfer the packets from the sender edge label switch router to the addressed edge label switch router by using a single label. In other words, the exchange of label is unnecessary in each label switch router and, therefore, the packet can be transferred at a higher speed.
  • each label switch router refers to label information which is stored in the route control unit 721 , and executes the transfer of the VoIP packet.
  • the present invention is not limited to the above embodiments and can variously be modified without departing the range of the spirit.
  • a personal computer in which an Internet telephone program is installed, instead of the telephone.
  • a telephone having an automatic answering function such as an answering telephone.
  • the telephone having an automatic answering function executes operations such as recording, reproducing, and transfer of a voice signal.
  • the IP network is not limited to the Internet, and a LAN and WAN using an Internet protocol may be employed.

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050232225A1 (en) * 2004-04-19 2005-10-20 Pelaez Mariana B System and method for routing calls in a wireless network using a single point of contact
US20060233109A1 (en) * 2005-04-15 2006-10-19 Yangbo Lin Method for monitoring and reporting events by media gateways
US20070030843A1 (en) * 2001-10-19 2007-02-08 Miller Frank W Voice over IP architecture
US11363134B2 (en) * 2018-06-12 2022-06-14 Orange Gateway and method for managing VoIP telephone service

Families Citing this family (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4161185B2 (ja) 2001-11-16 2008-10-08 日本電気株式会社 時刻同期データの伝送方法
US7088679B2 (en) * 2001-12-12 2006-08-08 Lucent Technologies Inc. Method and system for providing failure protection in a ring network that utilizes label switching
GB0203470D0 (en) * 2002-02-14 2002-04-03 Marconi Comm Ltd Port label switching
DE10212374B4 (de) * 2002-03-20 2005-12-08 Siemens Ag Lastverteilung auf periphere Einrichtungen eines paketbasierten Vermittlungssystems
US7480283B1 (en) * 2002-03-26 2009-01-20 Nortel Networks Limited Virtual trunking over packet networks
WO2003081852A1 (en) * 2002-03-26 2003-10-02 Nortel Networks Limited Virtual trunking over packet networks
US7065191B2 (en) * 2002-04-04 2006-06-20 General Instrument Corporation Method and system for budgeting resources dedicated to processing non-voice data traffic
US6898276B1 (en) 2002-05-31 2005-05-24 Verizon Communications Inc. Soft network interface device for digital broadband local carrier networks
US6961335B1 (en) 2002-05-31 2005-11-01 Verizon Communications Inc. Multi-layer ring architecture for fiber-to-the-home telco carrier network
KR100454502B1 (ko) * 2002-06-08 2004-10-28 한국전자통신연구원 아이피 라우터에서 ＶｏＩＰ 트래픽에 대한 ＱｏＳ를제공하는 장치 및 포워딩방법
KR100875037B1 (ko) * 2002-06-20 2008-12-19 주식회사 케이티 Ｉｐ망의 대역폭 산출 시스템 및 방법
KR100461728B1 (ko) * 2002-12-10 2004-12-17 한국전자통신연구원 라우터를 통한 ＤｉｆｆＳｅｒｖ 기반 ＶｏＩＰ ＱｏＳ제공 방법
US7558256B1 (en) * 2003-02-11 2009-07-07 Juniper Networks, Inc. Slim bandwidth reservation protocol over an IP network
US7283529B2 (en) * 2003-03-07 2007-10-16 International Business Machines Corporation Method and system for supporting a dedicated label switched path for a virtual private network over a label switched communication network
US7447150B1 (en) * 2003-05-16 2008-11-04 Nortel Networks Limited Automated path restoration for packet telephony
JP4829474B2 (ja) * 2004-01-30 2011-12-07 富士通株式会社 ネットワーク制御装置およびそのパス制御方法
CN1756186B (zh) * 2004-09-30 2010-04-28 华为技术有限公司 一种资源管理的实现方法
KR100684143B1 (ko) * 2004-12-14 2007-02-20 한국전자통신연구원 단순화된 ｍｐｌｓ 메커니즘을 이용하여 다양한 ｌ2ｖｐｎ서비스를 제공하기 위한 방법 및 장치
CN1294723C (zh) * 2004-12-17 2007-01-10 华为技术有限公司 移动ip突发流量的缓解调节方法
CN100438503C (zh) * 2005-10-26 2008-11-26 华为技术有限公司 一种选择路径的方法
CN101039256B (zh) * 2006-03-17 2011-08-24 中兴通讯股份有限公司 分组控制单元帧分段传输方法
CN101753418B (zh) * 2008-12-17 2013-01-16 华为技术有限公司 实现跨域资源隔离的方法、装置及系统
EP3693011A1 (en) 2014-04-18 2020-08-12 Auburn University Particulate vaccine formulations for inducing innate and adaptive immunity
US10033657B2 (en) * 2016-06-30 2018-07-24 Juniper Networks, Inc. Generating automatic bandwidth adjustment policies per label-switched path

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1222018A (zh) 1997-12-29 1999-07-07 三星电子株式会社 使用电缆网络的电话业务系统和电话业务方法
US6336129B1 (en) 1997-12-05 2002-01-01 Kabushiki Kaisha Toshiba Packet transfer method and node device using resource reservation or priority transfer control without requiring virtual connection merging
US6507577B1 (en) * 1998-11-12 2003-01-14 Nortel Networks Limited Voice over internet protocol network architecture
US6522627B1 (en) * 1998-11-12 2003-02-18 Nortel Networks Limited Managing internet protocol connection oriented services
US6529499B1 (en) * 1998-09-22 2003-03-04 Lucent Technologies Inc. Method for providing quality of service for delay sensitive traffic over IP networks
US6600735B1 (en) 1999-01-29 2003-07-29 Hitachi, Ltd. Internet telephone connection method, bandwidth controller and gate keeper
US6674744B1 (en) * 1998-09-22 2004-01-06 Lucent Technologies Inc. Point-to-point data transport over the internet utilizing label switching without IP headers
US6973033B1 (en) * 1999-12-30 2005-12-06 At&T Corp. Method and apparatus for provisioning and monitoring internet protocol quality of service

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6336129B1 (en) 1997-12-05 2002-01-01 Kabushiki Kaisha Toshiba Packet transfer method and node device using resource reservation or priority transfer control without requiring virtual connection merging
CN1222018A (zh) 1997-12-29 1999-07-07 三星电子株式会社 使用电缆网络的电话业务系统和电话业务方法
US6490274B1 (en) 1997-12-29 2002-12-03 Samsung Electronics Co., Ltd. Telephony service system employing cable network and telephony service method
US6529499B1 (en) * 1998-09-22 2003-03-04 Lucent Technologies Inc. Method for providing quality of service for delay sensitive traffic over IP networks
US6674744B1 (en) * 1998-09-22 2004-01-06 Lucent Technologies Inc. Point-to-point data transport over the internet utilizing label switching without IP headers
US6507577B1 (en) * 1998-11-12 2003-01-14 Nortel Networks Limited Voice over internet protocol network architecture
US6522627B1 (en) * 1998-11-12 2003-02-18 Nortel Networks Limited Managing internet protocol connection oriented services
US6600735B1 (en) 1999-01-29 2003-07-29 Hitachi, Ltd. Internet telephone connection method, bandwidth controller and gate keeper
US6973033B1 (en) * 1999-12-30 2005-12-06 At&T Corp. Method and apparatus for provisioning and monitoring internet protocol quality of service

Non-Patent Citations (8)

* Cited by examiner, † Cited by third party
Title
"Multiprotocol Label Switching Architecture", E. Rosen et al., Aug. 1999, http://tools.ietf.org/wg/mpls/draft-ietft-mpls-arch/draft-ietf-mpls-arch-06.txt, 52 pages.
"RFC 1889-RTP: A Transport Protocol for Real-Time Applications", H. Shulzrinne et al., Jan. 1996, http://www.faqs.org/rfcs/rfc1889.html, 60 pages.
"RFC 2205-Resource ReSerVation Protocol (RSVP)-Version 1 Functional Specification", R. Braden, Ed. et al., Sep. 1997, http://www.faqs.org/rfcs/rfc2205.html, 79 pages.
"RFC 2475-An Architecture for Differentiated Service" S. Blake et al., Dec. 1998, http://www.faqs.org/rfcs/rfc2475.html, 29 pages.
"RFC 2676- QoS Routing Mechanisms and OSPF Extensions", G. Apostolopoulos et al., Aug. 1999, http://www.ietf.org/rfcs/rfc2676.txt, 47 pages.
"RFC 2705-Media Gateway Control Protocol (MGCP) Version 1.0", M. Arango et al., Oct. 1999, http://www.faqs.org/rfcs/rfc2705.html, 102 pages.
"RFC 760-DoD standard Internet Protocol", Information Sciences Institute, University of Southern California, Marina del Rey, California, Jan. 1980, http://www.faqs.org/rfcs/rfc760.html, 32 pages.
Copy of The People's Republic of China Office Action dated Jan. 10, 2003 (English translation of same).

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070030843A1 (en) * 2001-10-19 2007-02-08 Miller Frank W Voice over IP architecture
US8040877B2 (en) * 2001-10-19 2011-10-18 Foundry Networks, Llc Voice over IP architecture
US20050232225A1 (en) * 2004-04-19 2005-10-20 Pelaez Mariana B System and method for routing calls in a wireless network using a single point of contact
US7512090B2 (en) * 2004-04-19 2009-03-31 Alcatel-Lucent Usa Inc. System and method for routing calls in a wireless network using a single point of contact
US20060233109A1 (en) * 2005-04-15 2006-10-19 Yangbo Lin Method for monitoring and reporting events by media gateways
US8134926B2 (en) * 2005-04-15 2012-03-13 Huawei Technologies Co., Ltd. Method for monitoring and reporting events by media gateways
US8614953B2 (en) 2005-04-15 2013-12-24 Huawei Technologies Co., Ltd. Method for monitoring and reporting events by media gateways
US11363134B2 (en) * 2018-06-12 2022-06-14 Orange Gateway and method for managing VoIP telephone service

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